Power semiconductor components are often powered by high voltages. In many cases, there is interest in being able to use the voltage applied as the input variable for open or closed loop control electronics. Since such open or closed loop control electronics are expediently devised to handle just low voltages, the high voltage applied to the power semiconductor component has to be firstly converted into a signal corresponding to the high voltage, the signal then being applied to the open or closed loop control electronics.
This can be done by means of a resistive voltage divider, for instance, but which, however, has the drawback of a not inconsiderable power loss. Although to get round this problem capacitive voltage dividers can be used, here, however, dividing the voltage, especially when a DC voltage is applied, may tend to drift because of leakage currents, necessitating a defined discharge of the capacitances which complicates the matter.